This application deals with the development, initial testing and evaluation of medical imaging systems, subsystems and intrinsic hardware and software. This grant is concerned with teleradiology which is the transmission of x-ray images from one place to another using ordinary telephone lines or other electronic transmission media. Its intended use is to send these x-ray images from remote geographic areas where radiologists are not available to centrally located facilities where they are available, so timely readings can be obtained. Diagnostic image assessment is a major research component because transmitted images must be sufficiently faithful to the original radiograph to support normal radiological practice at remote facilities. Human reaction research is important because a "'system" has human beings at both ends. If professional acceptance is lacking, the "system" will not work regardless of how well the equipment works. The ability to store images efficiently and economically and to retrieve them quickly enough for professionals to "accept" the system, and to use it, is a critical feature in a successful "system." Examining these problems, it becomes clear there are five "system" parts: the communications network; the archiving medium; the data acquisition system; the display console; and, the software (PACS). Expected results of this Phase I grant proposal are to elucidate a systems approach and develop, test and evaluate equipment in Phase II to improve the delivery of health are in medically underserved areas by the means of telecommunicating digital radiologic images. Experts agree that the economic advantages of replacing film-based radiography with digital systems could be enormous; one has calculated a $1 billion yearly saving on a national basis.